1
Supplementary Information
Effects of biodiversity on the functioning of trophic
groups and ecosystems
Bradley J. Cardinale, Diane S. Srivastava, J. Emmett Duffy, Justin P. Wright, Amy L.
Downing, Mahesh Sankaran, Claire Jouseau
Selection of studies
We collated reference lists from several recent informal surveys of biodiversityecosystem functioning research1-5, and supplemented these with our own search of the
ISI Web of Knowledge database using the keyword sequence species AND (diversity
OR richness) AND (community OR ecosystem) AND (function OR functioning OR
production OR productivity OR biomass OR predation OR decomposition OR
herbivory). To be included in our analysis, a study had to meet the following 8 criteria:
1. Study must focus on species richness rather than any other form of biological
diversity (genetic, functional group, etc.).
2. Study must be empirical, and directly manipulate richness as an independent
variable. Observational studies or experiments that indirectly manipulate
richness via another treatment (e.g., nutrient addition) were not considered.
3. Study must manipulate at least 3 species within a focal trophic group. If
richness was manipulated for multiple trophic groups, these must have been
independent so that separate effect sizes could be calculated.
4. Study must focus on what we refer to as a ‘top-down’ effect of biodiversity,
where a researcher measures a direct effect of richness in trophic group t on (i)
the aggregate abundance or biomass (per area or volume) of all species in t,
and/or (ii) the depletion of resources used by t, calculated as an instantaneous
rate of consumption, the difference between a known initial and final
concentration, or the difference between treatments and 0-species controls. We
distinguish these from studies focused on how the diversity of a resource (e.g.,
richness of leaf litter) has ‘bottom-up’ effects that propagate through a food web,
which were not performed at a sufficient number of trophic levels to be
considered in this review.
5. The study must focus on how species richness impacts the magnitude or rate of
the response variables. Other aspects of ecosystem functioning such as temporal
stability or invisibility were not considered.
6. Study must not duplicate data presented in another paper. When studies
overlapped, we chose the paper reporting the most complete information.
7. If a study measured the effect of species richness on a response variable at
multiple times, only the last available time point was included in our analysis as
this was the least likely to be influenced by transient dynamics.
2
8. If a study used an additive experimental design (i.e., abundance and/or biomass
is intentionally confounded with richness so that one can assess non-additive
species interactions), authors must specifically account for abundance or
biomass as a covariate, or report the observed and expected values so that the
difference can be taken as the effect attributable to diversity.
Summary of studies
In total we reviewed 184 papers, of which, 58 met the 8 criteria above. All of
these studies are listed at the end of the Supplementary Information. The 58 studies
used in our analyses reported results from 111 different experiments performed using a
wide variety of organisms in 4 different trophic groups inhabiting various types of
ecosystems (Supplementary Table 1 and Figure 1).
Supplementary Table 1. Sample sizes compiled for our meta-analysis. Data in each
cell give the number of measures of the diversity effect size (log ratio) for a given
trophic group, with observations divided among aquatic/terrestrial studies.
Trophic group t
(resource)
Plants
(nutrients/H2O)
Herbivores
(plant tissue)
Predators
(prey)
Detritivores
(organic matter)
N
Standing stock of t
11/39
12/2
6/0
5/1
76
Resource depletion
by t
2/12
8/1
11/8
17/11
70
Standing stock of t
11/37
12/2
6/0
5/1
74
Resource depletion
by t
2/10
9/1
8/8
16/9
63
LRm
LRmˆ
Marine
Estuarine (8%)
Coastal (8%)
Freshwater
Lakes (18%)
Streams (15%)
Other (2%)
Primary producers
Herbaceous plants (35%)
Micro/macroalgae (6%)
Other (1%)
Protists (11%)
Terrestrial
Temperate grasslands (34%)
Temperate forests (8%)
Agricultural (6%)
Other (1%)
Animals
Arachnids/Insects (18%)
Crustaceans (9%)
Gastropods (3%)
Other (1%)
Fungi (14%)
Bacteria (2%)
3
Supplementary Figure 1. Types of ecosystems (left) and organisms (right) included in
our meta-analysis. The percentage of all observations is given in parentheses.
Sample size and publication bias
One of the most common forms of publication bias is the failure to publish small
negative-result studies, which can lead to a positive bias in the mean effect size6. We
failed to find any evidence of such publication bias in the studies used in our metaanalysis. Specifically, there was no under-representation of studies with both low
sample size N and low effect size LRm , as indicated by the lack of a correlation between
LRm and either monoculture N or polyculture N (r = -0.04 and -0.03, respectively, P >
0.34 for one-sided tests). Note from Supplementary Table 1 that for two trophic groups
(decomposers and predators) we were only able to locate 6 studies apiece. Both groups
showed overall positive effects of diversity on standing stocks (P < 0.01); however,
with small sample sizes any bias in publication could have large effects (the file-drawer
problem7). However, even if there was a publication bias against non-significant results
in these two groups, there would need to be > 141 unpublished studies of each trophic
group centered on LRm = 0 to reverse the significance of our current results (following
methods in Rosenthal7). This suggests that all of the conclusions we report are robust to
publication bias.
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Cardinale, B.J., J.J. Weis, A.E. Forbes, K.J. Tilmon, and A.R. Ives. 2006.
Biodiversity as both a cause and consequence of resource availability: A study
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36.
Engelhardt, K.A.M., and M.E. Ritchie. 2001. Effects of macrophyte species
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Finke, D.L., and R.F. Denno. 2005. Predator diversity and the functioning of
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Ecology Letters 8:1299-1306.
Fox, J.W. 2002. Testing a simple rule for dominance in resource competition.
American Naturalist 159:305-319.
Fox, J.W. 2004. Effects of algal and herbivore diversity on the partitioning of
biomass within and among trophic levels. Ecology 85:549-559.
Fridley, J.D. 2002. Resource availability dominates and alters the relationship
between species diversity and ecosystem productivity in experimental plant
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Fridley, J.D. 2003. Diversity effects on productivity in different light and
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animal species richness: evidence from leaf-eating, aquatic insects. Oikos
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relation to the diversity of soil saprophytic fungi. Oecologia 139:98-107.
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yield and quality. Journal of Applied Ecology 22:185-198
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Spehn, E.M., A. Hector, J. Joshi, M. Scherer-Lorenzen, B. Schmid, E. BazeleyWhite, C. Beierkuhnlein, M.C. Caldeira, M. Diemer, P.G. Dimitrakopoulos, J.A.
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Jumpponen, J. Koricheva, P.W. Leadley, M. Loreau, A. Minns, C.P.H. Mulder,
G. O'Donovan, S.J. Otway, C. Palmborg, J.S. Pereira, A.B. Pfisterer, A. Prinz,
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F.I. Woodward, S. Yachi, J.H. Lawton. 2005. Ecosystem effects of biodiversity
manipulations in European grasslands. Ecological Monographs 75:37-63.
Steiner, C. F., T. L. Darcy-Hall, N. J. Dorn, E. A. Garcia, G. G. Mittelbach, and
J. M. Wojdak. 2005. The influence of consumer diversity and indirect
facilitation on trophic level biomass and stability. Oikos 110:556-566.
Straub, C.S., and W.E. Snyder. 2006. Species identity dominates the relationship
between predator biodiversity and herbivore suppression. Ecology 87:277–282.
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Oikos 81:389-397.
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Van Peer, L., I. Nijs, D. Reheul, and B. De Cauwer. 2004. Species richness and
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7
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58.
van Ruijven, J., and F. Berendse. 2005. Diversity-productivity relationships:
Initial effects, long-term patterns, and underlying mechanisms. Proceedings of
the National Academy of Sciences 102:695-700.
Wardle, D. A., G. W. Yeates, W. Williamson, and K. I. Bonner. 2003. The
response of a three trophic level soil food web to the identity and diversity of
plant species and functional groups. Oikos 102:45-56.
Weis, J.J., B.J. Cardinale, K.J. Forshay, and A.R. Ives. Empirical and theoretical
evidence that the effects of algal diversity on primary production change
predictably through successional time. Ecology, accepted.
Wilby, A., S.C. Villareal, L.P. Lan, K.L. Heong, and M.B. Thomas. 2005.
Functional benefits of predator species diversity depend on prey identity.
Ecological Entomology 30:497-501.
Wilsey, B.J., and H.W. Polley. 2004. Realistically low species evenness does not
alter grassland species-richness-productivity relationships. Ecology 85:26932700.
Wohl, D.L., S. Arora, and J.R. Gladstone. 2004. Functional redundancy supports
biodiversity and ecosystem function in a closed and constant environment.
Ecology 85:1534-1540.
Wojdak, J.M. 2005. Relative strength of top-down, bottom-up, and consumer
species richness effects on pond ecosystems. Ecological Monographs 75:489504.
List of studies not included in our meta-analysis (with reasons noted)
59.
Allison, G. 2004. The influence of species diversity and stress intensity on
community resistance and resilience. Ecological Monographs, 74:117-134. Does
not meet criterion 5.
60.
Bardgett, R.D., and R. Cook. 1998. Functional aspects of soil animal diversity in
agricultural grasslands. Applied Soil Ecology 10:263-276. Does not meet
criterion 2.
61.
Bardgett, R.D., and A. Shine. 1999. Linkages between plant litter diversity, soil
microbial biomass and ecosystem function in temperate grasslands. Soil Biology
and Biochemistry 31:317-332. Does not meet criterion 4.
62.
Bardgett, R.D., J.M. Anderson, V. Behan-Pelletier, L. Brussaard, D.C. Coleman,
C. Ettema, A. Moldenke, J.P. Schimel, and D.H. Wall. 2001. The influence of
soil biodiversity on hydrological pathways and the transfer of materials between
terrestrial and aquatic ecosystems. Ecosystems 5:421-429. Does not meet
criterion 2.
63.
Bergamini, A., D. Pauli, M. Peintinger, and B. Schmid. 2001. Relationships
between productivity, number of shoots and number of species in bryophytes
and vascular plants. Journal of Ecology, 89: 920-929. Does not meet criterion 2.
64.
Berish C.W., and J.J. Ewel. 1988. Root development in simple and complex
tropical successional ecosystems. Plant and Soil 106:73-84. Does not meet
criterion 2.
65.
Bezemer, T. M., O. Graca, P. Rousseau, and W.H. van der Putten. 2004. Aboveand belowground trophic interactions on creeping thistle (Cirsium arvense) in
high- and low-diversity plant communities: Potential for biotic resistance? Plant
Biology, 6:231-238. Does not meet criterion 5.
8
66.
67.
68.
69.
70.
71.
72.
73.
74.
75.
76.
77.
78.
79.
Biles, C.L., M. Solan, I. Isaksson, D.M. Paterson, C. Emes, and D.G. Raffaelli.
2003. Flow modifies the effect of biodiversity on ecosystem functioning: an in
situ study of estuarine sediments. Journal of Experimental Marine Biology and
Ecology 285, 165-177. Does not meet criterion 4.
Bradford, M.A., T.H. Jones, R.D. Bardgett, H. Black, B. Boag, M. Bonkowski,
R. Cook, T. Eggers, A.C. Gange, S.J. Grayston, E. Kandeler, A.E. McCaig, J.E.
Newington, H. Setala, P.L. Staddon, G.M. Tordoff, D. Tshcerko, and J.H.
Lawton. 2002. Impacts of soil faunal community composition on model
grassland ecosystems. Science, 298: 615-618. Does not meet criterion 1.
Bret-Harte, M.S., E.A. Garcia, V.M. Sacre, J.R. Whorley, J.L. Wagner, S.C.
Lippert, and F.S. Chapin. 2004. Plant and soil responses to neighbour removal
and fertilization in Alaskan tussock tundra. Journal of Ecology, 92:635-347.
Does not meet criterion 4.
Brinkman, E. P., H. Duyts, and W.H. van der Putten. 2005. Consequences of
variation in species diversity in a community of root feeding herbivores for
nematode dynamics and host-plant biomass. Oikos 110:417-427. Does not meet
criterion 4.
Brown, B.J., and J.J. Ewel. 1987. Herbivory in complex and simple tropical
successional ecosystems. Ecology 68:108-16. Does not meet criterion 2.
Brown, R.L. and J.D. Fridley. 2003. Control of plant species diversity and
community invasibility by species immigration: seed richness versus seed
density. Oikos 102:15-24 enhances agricultural production. Ecology Letters
4:185-189. Does not meet criterion 5.
Bullock, J.M., R.F. Pywell, M.J.W. Burke, and K.J. Walker. 2001. Restoration
of biodiversity enhances agricultural production. Ecology Letters 4:185-189.
Does not meet criterion 2.
Caldeira, M.C., R.J. Ryel, J.H. Lawton, and J.S. Pereira. 2001. Mechanisms of
positive biodiversity-production relationships: insights provided by delta C-13
analysis in experimental Mediterranean grassland plots. Ecology Letters 4:43943. Does not meet criterion 5 (cross reference Spehn et al. 2005).
Carney, K.M., and P.A. Matson. 2005. Plant communities, soil microorganisms,
and soil carbon cycling: Does altering the world belowground matter to
ecosystem functioning? Ecosystems, 8:928-940. Does not meet criterion 4.
Cragg, R.G., and R.D. Bardgett. 2001. How changes in soil faunal diversity and
composition within a trophic group influence decomposition processes. Soil
Biology and Biochemistry 33:2073-2081. Does not meet criterion 4.
Cochran-Stafira, D.L., and C.N. von Ende. 1998. Integrating bacteria into food
webs: Studies with Sarracenia purpurea inquilines. Ecology 79:880-898. Does
not meet criterion 3.
Crawley, M.J., S.L. Brown, M.S. Heard, and G.R. Edwards. 1999. Invasionresistance in experimental grassland communities: species richness or species
identity? Ecology Letters 2:140-148. Does not meet criterion 5.
Dangles, O., and B. Malmqvist. 2004. Species richness-decomposition
relationships depend on species dominance. Ecology Letters 7:395-402. Does
not meet criterion 2.
De Deyn, G.B., C.E. Raaijmakers, and W.H. Van der Putten. 2004. Plant
community development is affected by nutrients and soil biota. Journal of
Ecology 92:824-34. Does not meet criterion 2.
9
80.
81.
82.
83.
84.
85.
86.
87.
88.
89.
90.
91.
92.
93.
94.
De Deyn, G. B., C. E. Raaijmakers, J. van Ruijven, F. Berendse, and W. H. van
der Putten. 2004. Plant species identity and diversity effects on different trophic
levels of nematodes in the soil food web. Oikos 106:576-586. Does not meet
criterion 4.
Dodd, M.E., J. Silvertown, K. McConway, J. Potts, and M. Crawley. 1994.
Stability in the plant-communities of the Park-Grass experiment - the
relationships between species richness, soil pH and biomass variability.
Philosophical Transactions of the Royal Society of London Series B-Biological
Sciences 346: 185-93. Does not meet criterion 2 or 5.
Downing, A.L., and M.A. Leibold. 2002. Ecosystem consequences of species
richness and composition in pond food webs. Nature 416: 837-41. Does not
meet criterion 3.
Downing, A.L. 2005. Relative effects of species composition and richness on
ecosystem properties in ponds. Ecology, 86, 701-715. Does not meet criterion 3.
Dukes, J.S. 2001. Biodiversity and invasibility in grassland microcosms.
Oecologia 126:563-568. Does not meet criterion 5.
Dukes, J.S. 2002. Species composition and diversity affect grassland
susceptibility and response to invasion. Ecological Applications 12:602-617.
Does not meet criterion 5.
Emmerson, M.C., M. Solan, C. Emes, D.M. Paterson, and D. Raffaelli. 2001.
Consistent patterns and the idiosyncratic effects of biodiversity in marine
ecosystems. Nature 411:73-77. Does not meet criterion 4.
Engelhardt, K.A.M., and M.E. Ritchie. 2002. The effect of aquatic plant species
richness on wetland ecosystem processes. Ecology 83:2911-2924. Does not meet
criterion 6 (cross reference Engelhardt & Ritchie 2001).
Ewel, J.J., M.J. Mazzarino, and C.W. Berish. 1991. Tropical soil fertility
changes under monocultures and successional communities of different
structure. Ecological Applications 1:289-302. Does not meet criterion 2.
Fargione, J.E. and D. Tilman. 2005. Diversity decreases invasion via both
sampling and complementarity effects. Ecology Letters 8:604-611. Does not
meet criterion 5.
Feinsinger, P., J.A. Wolfe, and L.A. Swarm. 1982. Island ecology: reduced
hummingbird diversity and the pollination biology of plants, Trinidad and
Tobago, West Indies. Ecology 63:494-506. Does not meet criterion 2.
Finke. D.L., and R.F. Denno. 2004. Predator diversity dampens trophic cascades.
Nature 429:407-410. Does not meet criterion 8.
Foster, B.L., and T.L. Dickson. 2004. Grassland diversity and productivity: The
interplay of resource availability and propagule pools. Ecology 85:1541-1547.
Does not meet criterion 2.
France, K.E., and J.E. Duffy. 2006. Diversity and dispersal interactively affect
predictability of ecosystem function. Nature 441:1139-1143. Metrics for
diversity effect size could not be calculated because study does not include
species monocultures.
Gastine, A., M. Scherer-Lorenzen, and P.W. Leadley. 2003. No consistent
effects of plant diversity on root biomass, soil biota and soil abiotic conditions in
temperate grassland communities. Applied Soil Ecology 24:101-111. Does not
meet criterion 6 (cross reference Spehn et al. 2005).
10
95.
96.
97.
98.
99.
100.
101.
102.
103.
104.
105.
106.
107.
108.
109.
Griffiths, B.S., et al. 2000. Ecosystem response of pasture soil communities to
fumigation-induced microbial diversity reductions: an examination of the
biodiversity-ecosystem function relationship. Oikos 90: 279-94. Does not meet
criterion 2.
Griffiths B.S., et al. 2001. An examination of the biodiversity-ecosystem
function relationship in arable soil microbial communities. Soil Biology and
Biochemistry 33:1713-22. Metrics for diversity effect size could not be
calculated because study does not include species monocultures.
Hagele, B.F., and M. Rowell-Rahier. 1999. Dietary mixing in three generalist
herbivores: nutrient complementation or toxin dilution? Oecologia, 119:521-533.
Does not meet criterion 4.
Hattenschwiler, S., and D. Bretscher. 2001. Isopod effects on decomposition of
litter produced under elevated CO2, N deposition and different soil types. Global
Change Biology 7:565-579. Does not meet criterion 4.
Hattenschwiler, S., and P. Gasser. 2005. Soil animals alter plant litter diversity
effects on decomposition. Proceedings of the National Academy of Sciences of
the United States of America 102:1519-1524. Does not meet criterion 4.
Hawkins, B.A., 1993. Parasitoid richness, host mortality, and biological control.
American Naturalist 141:634-641. Does not meet criterion 2.
Hector, A., et al. 1999. Plant diversity and productivity experiments in European
grasslands. Science 286:1123-1127. Does not meet criterion 6 (cross reference
Spehn et al 2005).
Hector, A., A.J. Beale, A. Minns, S.J. Otway, and J.H. Lawton. 2000.
Consequences of the reduction of plant diversity for litter decomposition: effects
through litter quality and microenvironment. Oikos 90: 357-71. Does not meet
criterion 4.
Heemsbergen, D.A., M.P. Berg, M. Loreau, J.R. van Hal, J.H. Faber, and H.A.
Verhoef. 2004. Biodiversity effects on soil processes explained by interspecific
functional dissimilarity. Science 306: 1019-20. Metrics for diversity effect size
could not be calculated because study does not include species monocultures.
Hiremath, A.J., and J.J. Ewel. 2001. Ecosystem nutrient use efficiency,
productivity, and nutrient accrual in model tropical communities. Ecosystems
4:669-682. Does not meet criterion 8.
Hooper, D., and P. Vitousek. 1997. The effects of plant composition and
diversity on ecosystem processes. Science 277:1302-1305. Does not meet
criterion 1.
Hooper, D.U., and P.M. Vitousek. 1998. Effects of plant composition and
diversity on nutrient cycling. Ecological Monographs 68:121-149. Does not
meet criterion 1.
Hooper, D.U., and J.S. Dukes. 2004. Overyielding among plant functional
groups in a long-term experiment. Ecology Letters 7: 95-105. Does not meet
criterion 1.
Hughes, A.R., and J.J. Stachowicz. 2004. Genetic diversity enhances the
resistance of a seagrass ecosystem to disturbance. Proceedings of the National
Academy of Sciences USA 101:8998-9002. Does not meet criterion 1.
Jonsson, M., B. Malmqvist, and P.O. Hoffsten. 2001. Leaf litter breakdown rates
in boreal streams: does shredder species richness matter? Freshwater Biology
46:161-171. Does not meet criterion 2.
11
110.
111.
112.
113.
114.
115.
116.
117.
118.
119.
120.
121.
122.
123.
124.
Joshi, J., D. Matthies, and B. Schmid. 2000. Root hemiparasites and plant
diversity in experimental grassland communities. Journal of Ecology 88:634-44.
Does not meet criterion 5.
Kennedy, T.A., S. Naeem, K.M. Howe, J.M.H. Knops, D. Tilman, and P. Reich.
2002. Biodiversity as a barrier to ecological invasion. Nature 417:636-638.
Does not meet criterion 5.
Kahmen, A., J. Perner, V. Audorff, W. Weisser, and N. Buchmann. 2005.
Effects of plant diversity, community composition and environmental
parameters on productivity in montane European grasslands. Oecologia 142:606615. Does not meet criterion 2.
Klironomos, J.N., J. McCune, M. Hart, and J. Neville. 2000. The influence of
arbuscular mycorrhizae on the relationship between plant diversity and
productivity. Ecology Letters, 3:137-141. Does not meet criterion 4.
Knops, J.M.H., D. Wedin, and D. Tilman. 2001. Biodiversity and decomposition
in experimental grassland ecosystems. Oecologia 126:429-33. Does not meet
criterion 4.
Knops, J.M.H., et al. 1999. Effects of plant species richness on invasion
dynamics, disease outbreaks, insect abundances and diversity. Ecology Letters
2:286-93. Does not meet criterion 5.
Koricheva, J., C.P.H. Mulder, B. Schmid, J. Joshi, and K. Huss-Danell. 2000.
Numerical responses of different trophic groups of invertebrates to
manipulations of plant diversity in grasslands. Oecologia 125:271-282. Does
not meet criterion 4.
Kruess, A., and T. Tscharntke. 1994. Habitat fragmentation, species loss, and
biological control. Science 264:1581-1584. Does not meet criterion 2.
Laakso, J., and H. Setala. 1999. Sensitivity of primary production to changes in
the architecture of belowground food webs. Oikos 87: 57-64. Does not meet
criterion 3.
Larsen, T.H., N.M. Williams, and C. Kremen. 2005. Extinction order and
altered community structure rapidly disrupt ecosystem functioning. Ecology
Letters, 8: 538-547. Does not meet criterion 2.
Lawler, S.P. 1993. Species richness, species composition and populationdynamics of protists in experimental microcosms. Journal of Animal Ecology
62:711-719. Does not meet criterion 5.
Leps, J., et al. 2001. Separating the chance effect from other diversity effects in
the functioning of plant communities. Oikos 92:123-134. Paper does not
provide estimates of standard errors or standard deviations of the diversity
treatments.
Leroy, C. J., and J. C. Marks. 2006. Litter quality, stream characteristics and
litter diversity influence decomposition rates and macroinvertebrates Freshwater
Biology 51:605-617. Does not meet criterion 4.
Lecerf, A., M. Dobson, C.K. Dang, and E. Chauvet. 2005. Riparian plant
species loss alters trophic dynamics in detritus-based stream ecosystems.
Oecologia 146:432-442. Does not meet criterion 4.
Liiri, M., et al. 2002. Relationship between soil microarthropod species
diversity and plant growth does not change when the system is disturbed. Oikos
96, 137-149. Does not meet criterion 4.
12
125.
126.
127.
128.
129.
130.
131.
132.
133.
134.
135.
136.
137.
138.
139.
Lyons, K.G., and M.W. Schwartz. 2001. Rare species loss alters ecosystem
function - invasion resistance. Ecology Letters 4:358-365. Does not meet
criterion 5.
McGrady-Steed, J., P.M. Harris, and P.J. Morin. 1997. Biodiversity regulates
ecosystem predictability. Nature 390:162-165. Does not meet criterion 3.
McGrady-Steed, J., and P. J. Morin. 2000. Biodiversity, density compensation,
and the dynamics of populations and functional groups. Ecology 81:361-373.
Does not meet criterion 5.
McNaughton, S.J. 1985. Ecology of a grazing ecosystem: the Serengeti.
Ecological Monographs 55: 259-94. Does not meet criterion 2.
Mermillod-Blondin, F., F. Francois-Carcaillet, and R. Rosenberg. 2005.
Biodiversity of benthic invertebrates and organic matter processing in shallow
marine sediments: an experimental study. Journal of Experimental Marine
Biology and Ecology, 315:187-209. Does not meet criterion 4.
Mikola, J. 1998. Effects of microbivore species composition and basal resource
enrichment on trophic-level biomasses in an experimental microbial-based soil
food web. Oecologia 117:396-403. Metrics for diversity effect size could not be
calculated because study does not include species monocultures.
Mikola, J., and H. Setälä. 1998. Relating species diversity to ecosystem
functioning: mechanistic backgrounds and experimental approach with a
decomposer food web. Oikos 83: 180-94. Metrics for diversity effect size could
not be calculated because study does not include species monocultures.
Milcu, A., S. Partsch, R. Langel, and S. Scheu. The response of decomposers
(earthworms, springtails and microorganisms) to variations in species and
functional group diversity of plants. Oikos 112:513-524. Does not meet
criterion 4.
Mitchell, C.E., D. Tilman, and J.V. Groth. 2002. Effects of grassland plant
species diversity, abundance, and composition on foliar fungal disease. Ecology
83:1713-1726. Does not meet criterion 4.
Montoya, J.M., M.A. Rodriguez, and B.A. Hawkins. 2003. Food web
complexity and higher-level ecosystem services. Ecology Letters 6:587-93. Does
not meet criterion 2.
Moore, T.N., and P.G. Fairweather. 2006. Decay of multiple species of seagrass
detritus is dominated by species identity, with an important influence of mixing
litters. Oikos 114:329-337. Does not meet criterion 4.
Mulder C.P.H., J. Koricheva, K. Huss-Danell, P. Hogberg, and J. Joshi. 1999.
Insects affect relationships between plant species richness and ecosystem
processes. Ecology Letters 2:237-246. Does not meet criterion 4.
Mulder C.P.H., A. Jumpponen, P. Hogberg, and K. Huss-Danell. 2002. How
plant diversity and legumes affect nitrogen dynamics in experimental grassland
communities. Oecologia 133: 412-21. Does not meet criterion 6 (cross reference
Spehn et al. 2005)
Naeem, S., J.M.H. Knops, D. Tilman, K.M. Howe, T. Kennedy, and S. Gale.
2000. Plant diversity increases resistance to invasion in the absence of covarying
extrinsic factors. Oikos 91: 97-108. Does not meet criterion 5.
Naeem, S., L.J. Thomson, S.P. Lawler, J.H. Lawton, and R.M. Woodfin. 1995.
Empirical evidence that declining species diversity may alter the performance of
13
140.
141.
142.
143.
144.
145.
146.
147.
148.
149.
150.
151.
152.
153.
terrestrial ecosystems. Proceedings of the Royal Society of London Series BBiological Sciences B347: 249-62. Does not meet criterion 3.
Naeem, S., L.J. Thompson, S.P. Lawler, J.H. Lawton, and R.M. Woodfin. 1994.
Declining biodiversity can alter the performance of ecosystems. Nature 368:734736. Does not meet criterion 3.
Naeem, S., and S.B. Li. 1998. Consumer species richness and autotrophic
biomass. Ecology 79: 2603-2615. Does not meet criterion 3.
Naeem, S., D.R. Hahn, and G. Schuurman. 2000. Producer-decomposer codependency influences biodiversity effects. Nature 403:762-764. This study does
meet our criteria; however, (i) We cannot extract data reliably from the 3dimensional graph given in figure 2, and (ii) paper does not report standard
deviations for the algal x bacterial richness combinations.
Niklaus, P.A., P.W. Leadley, B. Schmid, and C.H. Korner. 2001. A long term
field study on biodiversity x elevated CO2 interactions in grassland. Ecological
Monographs 71:341-56. Does not meet criterion 6 (cross reference Niklaus et
al. Oecologia 2001).
Niklaus, P.A. E. Kandeler, P.W. Leadley, B. Schmid, D. Tscherko, and C.
Korner. 2001. A link between plant diversity, elevated CO2 and soil nitrate.
Oecologia 127:540-548. Metrics for diversity effect size could not be calculated
because study does not include species monocultures.
Nilsson, M., D.A. Wardle, and A. Dahlberg. 1999. Effects of plant litter species
composition and diversity on the boreal forest plant-soil system. Oikos 86:1626. Does not meet criterion 4.
Ostfeld, R.S., and K. LoGiudice. 2003. Community disassembly, biodiversity
loss, and the erosion of an ecosystem service. Ecology, 84, 1421-1427. Does not
meet criterion 2.
Petchey, O.L., P.T. McPhearson, T.M. Casey, and P.J. Morin. 1999.
Environmental warming alters food-web structure and ecosystem function.
Nature 402:69-72. Does not meet criterion 3.
Pfisterer, A. B., M. Diemer, and B. Schmid. 2003. Dietary shift and lowered
biomass gain of a generalist herbivore in species-poor experimental
communities. Oecologia, 135:234-241. Does not meet criterion 4.
Ruesink, J.L., and D.S. Srivastava. 2001. Numerical and per capita responses to
species loss: mechanisms maintaining ecosystem function in a community of
stream insect detritivores. Oikos 93. Does not meet criterion 3.
Salamon, J.A., M. Schaefer, J. Alphei, B. Schmid, and S. Scheu. 2004. Effects of
plant diversity on Collembola in an experimental grassland ecosystem. Oikos
106:51-60. Does not meet criterion 4.
Scherber, C., P.N. Mwangi, V.M. Temperton, C. Roscher, J. Schumacher, B.
Schmid, and W.W. Weisser. 2006. Effects of plant diversity on invertebrate
herbivory in experimental grassland. Oecologia, 147: 489-500. Does not meet
criterion 4.
Sankaran, M., and S.J. McNaughton. 1999. Determinants of biodiversity
regulate compositional stability of communities. Nature 401:691-693. Does not
meet criterion 2.
Scherer-Lorenzen, M. 1999. Effects of plant diversity on ecosystem processes in
experimental grassland communities. Bayreuther Forum Ökologie 75:1-195.
Does not meet criterion 6 (cross reference Spehn et al. 2005).
14
154.
155.
156.
157.
158.
159.
160.
161.
162.
163.
164.
165.
166.
167.
168.
Scheu, S., N. Schlitt, A.V. Tiunov, J.E. Newington, and T.H. Jones. 2002.
Effects of the presence and community composition of earthworms on microbial
community functioning. Oecologia 133:254-260. Does not meet criterion 4, and
metrics for diversity effect size could not be calculated because study does not
include species monocultures.
Schlapfer, F., A.B. Pfisterer, and B. Schmid. 2005. Non-random species
extinction and plant production: implications for ecosystem functioning. Journal
of Applied Ecology 42:13-24. Does not meet criterion 2.
Setala, H. 2002. Sensitivity of ecosystem functioning to changes in trophic
structure, functional group composition and species diversity in belowground
food webs. Ecological Research 17:207-215. Does not meet criterion 2.
Siemann, E., D. Tilman, J. Haarstad, and M. Ritchie. 1998. Experimental tests of
the dependence of arthropod diversity on plant diversity. American Naturalist
152:738-750. Does not meet criterion 4.
Stachowicz, J.J., H. Fried, R.W. Osman, and R.B. Whitlatch. 2002. Biodiversity,
invasion resistance, and marine ecosystem function: Reconciling pattern and
process. Ecology 83: 2575-90. Does not meet criterion 5.
Stachowicz, J.J., R.B. Whitlatch, and R.W. Osman. 1999. Species diversity and
invasion resistance in a marine ecosystem. Science 286:1577-1579. Does not
meet criterion 5 or 6 (cross reference Stachowicz et al. 2002).
Steiner, C.F. 2001. The effects of prey heterogeneity and consumer identity on
the limitation of trophic-level biomass. Ecology 82:2495-2506. Does not meet
criterion 2.
Stocker, R., C. Korner, B. Schmid, P.A. Niklaus, and P.W. Leadley. 1999. A
field study of the effects of elevated CO2 and plant species diversity on
ecosystem-level gas exchange in a planted calcareous grassland. Global Change
Biology 5:95-105. Metrics for diversity effect size could not be calculated
because study does not include species monocultures.
Sullivan, G., and J.B. Zedler. 1999. Functional redundancy among tidal marsh
halophytes: a test. Oikos, 84:246-260. Does not meet criterion 2.
Swan, C.M., and M.A. Palmer. 2004. Leaf diversity alters litter breakdown in a
Piedmont stream. J. North American Benthological Society 23:15-28. Does not
meet criterion 4.
Swan C.M., and M.A. Palmer. 2006. Composition of speciose leaf litter alters
stream detritivore growth, feeding activity and leaf breakdown. Oecologia
147:469-478. Does not meet criterion 4.
Swan, C.M., and M.A. Palmer. In press. Preferential feeding by an aquatic
consumer mediates non-additive decomposition of speciose leaf litter.
Oecologia. Does not meet criterion 4.
Symstad, A. J., E. Siemann, and J. Haarstad. 2000. An experimental test of the
effect of plant functional group diversity on arthropod diversity. Oikos 89:243253. Does not meet criterion 4.
Tilman, D., and J.A. Downing. 1994. Biodiversity and stability in grasslands.
Nature 367:363-365. Does not meet criterion 2.
Tilman, D. 1996. Biodiversity: Population versus ecosystem stability. Ecology
77:350-363. Does not meet criterion 2.
15
169.
170.
171.
172.
173.
174.
175.
176.
177.
178.
179.
180.
181.
182.
Tilman, D., J. Knops, D. Wedin, P. Reich, M. Ritchie, and E. Siemann. 1997.
The influence of functional diversity and composition on ecosystem processes.
Science 277: 1300-1302. Does not meet criterion 1.
Troumbis, A.Y., P.G. Dimitrakopoulos, A.S.D. Siamantziouras, and D.
Memtsas. 2000. Hidden diversity and productivity patterns in mixed
Mediterranean grasslands. Oikos 90:549-559. Does not meet criterion 6 (cross
reference Spehn et al. 2005).
Troumbis, A.Y., and D. Memtsas. 2000. Observational evidence that diversity
may increase productivity in Mediterranean shrublands. Oecologia 125: 101-8.
Does not meet criterion 2.
Van Ruijven, J., G.B. De Deyn, and F. Berendse. 2003. Diversity reduces
invasibility in experimental plant communities: the role of plant species.
Ecology Letters 6: 910-918. Does not meet criterion 5.
van Ruijven, J., and F. Berendse. 2003. Positive effects of plant species diversity
on productivity in the absence of legumes. Ecology Letters, 6:170-175. Does
not meet criterion 6 (cross reference van Ruijven & Berendse 2005).
Vila, M., J. Vayreda, C. Gracia, and J.J. Ibanez. 2003. Does tree diversity
increase wood production in pine forests? Oecologia 135: 299-303. Does not
meet criterion 2.
Vinebrooke, R.D., D.W. Schindler, D.L. Findlay, M.A. Turner, M. Paterson, and
K.H. Milis. 2003. Trophic dependence of ecosystem resistance and species
compensation in experimentally acidified lake 302S (Canada). Ecosystems
6:101-113. Does not meet criterion 2.
Wardle, D.A., and K.S. Nicholson. 1996. Synergistic effects of grassland plant
species on soil microbial biomass and activity: Implications for ecosystem-level
effects of enriched plant diversity. Functional Ecology 10:410-416. Does not
meet criterion 3.
Wardle, D.A., O. Zackrisson, G. Hornberg, C. Gallet. 1997. The influence of
island area on ecosystem properties. Science 277: 1296-1299. Does not meet
criterion 2.
Wardle, D.A., K.I. Bonner, and G.M. Barker. 2000. Stability of ecosystem
properties in response to aboveground functional group richness and
composition. Oikos 89:11-23. Does not meet criterion 1.
Wardle, D.A., et al., Oikos. 1997. Biodiversity and plant litter: Experimental
evidence which does not support the view that enhanced species richness
improves ecosystem function. Oikos 79:247-258. Does not meet criterion 4.
Wardle, D.A., G.W. Yeates, W.M. Williamson, K.I. Bonner, and G.M. Barker.
2004. Linking aboveground and belowground communities: the indirect
influence of aphids species identity and diversity on a three trophic level soil
food web. Oikos, 107:283-294. Does not meet criterion 4.
Wilsey, B.J. and H.W. Polley. 2002. Reductions in grassland species evenness
increase dicot seedling invasion and spittle bug infestation. Ecology Letters
5:676-684. Does not meet criterion 5.
Zak, D.R., W.E. Holmes, D.C. White, A.D. Peacock, and D. Tilman. 2003. Plant
diversity, soil microbial communities, and ecosystem function: Are there any
links? Ecology 84: 2042-50. Does not meet criterion 4.
16
183.
184.
Zavaleta, E.S. and K.B. Hulvey. 2004. Realistic species losses
disproportionately reduce grassland resistance to biological invaders. Science
306:1175-1177. Does not meet criterion 5.
Zimmer, M., G. Kautz, and W. Topp. 2005. Do woodlice and earthworms
interact synergistically in leaf litter decomposition? Functional Ecology 19:7-16.
Does not meet criterion 3.